Natural Factors Magnesium Bisglycinate Elemental 400mg - Provides 400 mg of elemental magnesium in a highly absorbable and easy-to-mix powdered form. Magnesium helps maintain proper muscle function, including the heart muscle. It also supports energy metabolism and helps in the development and maintenance of bones and teeth. This non-GMO, vegan-friendly powder is gentle on the stomach and does not rely on stomach acid for absorption. Simply mix one serving into water daily.